Mobile issues: BigGrid Offset posts, module title font size, menu/search bg img

Note: I disabled the “Mobile theme” plugin because I would rather the mobile version of the website be based on responsive web design.
The website with issues:

wuche.gg

Issues with responsive web on mobile (Android, but presumably iOS as well)

1. On the front page Big Grids, the offset posts feature works on desktop browsers but does not work on mobile browsers. All Big Grids are set to sort by -Latest-.

2. I’m using custom css for the module title fonts on Big Grid Full 1 & 2 because the option to change it via module on Theme Fonts isn’t implemented yet.

.td_block_big_grid_fl_1 .td-module-title a{
font-family: ‘Source Sans Pro’, sans-serif;
font-weight: 600;
font-size: 42px;
line-height: 44px;
}
.td_block_big_grid_fl_2 .td-module-title a{
font-family: ‘Source Sans Pro’, sans-serif;
font-weight: 600;
font-size: 26px;
line-height: 28px;
}

It works perfectly, but I want it to be responsive as well and downsize the font when below a certain width. So I added this code also to Big Grid Full 1 just to test out:

@media (max-width: 767px) {
.td_block_big_grid_fl_1 .td-module-title a{
font-size:30px!important
} }

@media (max-width: 767px) {
.td_block_big_grid_fl_1 .td-module-title a{
line-height:32px!important
} }

And while it works this works perfectly on desktop, it does not work on mobile.

3. I deleted/changed the background image for mobile menu / search background, but it still persists.

Whenever I make an update, I clear the cache on Google Chrome on my Android phone. I also empty the cache via WordPress, and I also have disabled the WP Super Cache plugin just to triple check.

Any help would be greatly appreciated. Please and thank you!

Update on point 3: I checked on my desktop browser and the new background image for mobile menu/search background seems to be working properly when reducing browser width below 767, but the old image still persists when visiting on my Android smartphone on Google Chrome. Could this be some cache issue I’m overlooking?

Update: I’ve checked my website on someone else’s iPhone and all three issues are almost certainly a caching issue.

So let me rephrase my issues 😛

1. How do I fully empty the cache on both Android and iPhone for testing? Because I manually empty cache on Safari and Chrome and new updates are still not reflected.

2. Is there a way to force a visitor to see the most recent version of my website?

Thanks!

Thanks!